The present invention relates generally to sighting aids for shotguns, and, more particularly, to a method and apparatus that aids a shooter in maintaining the aiming eye at a proper elevation relative the rib and bead of a shotgun.
Shotgun sights differ significantly from the sights used on rifles and other firearms. Since a shotgun fires a pattern of pellets rather than a single slug, speed of aiming and pointing are generally more important than precise accuracy. For example, bird hunting, and trap shooting both demand aiming at comparatively close, fast-moving targets, as opposed to rifle shooting, where the target is usually at a longer range and the angular rate of movement is much slower.
Because of these different requirements, the sights used on other types of long arms are generally unsuitable for shotguns. For example, conventional iron sights for rifles generally have an open orxe2x80x9cpeepxe2x80x9d rear sight on the receiver and a bead at the muzzle end of the barrel, the goal being to achieve very precise alignment in both elevation and azimuth. However, this arrangement requires comparatively slow and deliberate aiming, and moreover the sight picture is comparatively small, so that these types of sights are generally ill suited for use on shotguns. Telescopic rifle sights can achieve even greater accuracy, but for similar reasons they too are unsuitable for use on shotguns (except for deer hunting and other specialized applications where the gun fires a single slug as opposed to a pattern of pellets).
Shotgun sights, by contrast, ordinarily lack a rear sight aperture. Instead, there is usually a rib along the top of the barrel (or between the barrels in the case of a side-by-side), with a small bead being mounted at the forward end of the rib. Although this arrangement permits extremely fast and effective aiming when firing at close, fast moving targets, it does present certain challenges that can be very difficult to master.
One particular difficulty is that of maintaining the aiming eye at the proper level relative to the barrel. Since there is no rear sight opening to look through, proper elevation of the barrel depends on the user keeping his aiming eye closely level with the rib, usually with the cheek held against the stock and the eye looking just over the top of the receiver. However, this is easier said than done; similar to the situation with a golf swing, there is a recurring tendency for the shooter to lift his head and raise his eye above the proper level. As the shooter raises his head, there is a tendency to raise the front bead as well, with the result that the barrel is elevated too high and the shot misses the target.
To illustrate this situation, FIG. 1 shows a shotgun 01 having conventional sights, consisting up of a rib 02 that extends along the top of the barrel 03 and a front bead 04 that is mounted proximate the forward end of the barrel. As noted above, proper aiming requires that the sighting eye be held essentially level with the rib 02, looking forward over the top of the receiver 05. However, as can be seen in FIG. 2, inadvertent lifting of the head causes the aiming eye 06 to be raised above the proper level, so that when the front bead 04 its positioned on the line of sight 07 from the eye to the target 08 the barrel is in fact angled too high and the shot passes over the target, as indicated by arrow 09.
This is an extremely common problem, and is perhaps most pronounced when firing multiple shots in quick succession, since the first shot tends to break the shooter""s concentration and the recoil also causes the gun to move rearwardly and downwardly relative to the aiming eye. As a result, shooters constantly have to remind themselves to keep their heads down, but in the absence of an effective visual reference it is in fact very difficult to keep the aiming eye at the proper level under such circumstances.
A great many types of sights have, of course, been used or proposed over the long history of firearms. However, the vast majority have been variations on the typical arrangement of front and rear sights used on rifles, usually with the goal of achieving precision accuracy. Most are therefore unsuitable for shotgun use. Consequently, the problem of keeping the aiming eye at the proper level relative to the rib of a shotgun has remained unresolved.
Another, somewhat related difficulty is that of cross dominance, wherein the non-sighting eye becomes dominant and the barrel becomes misaligned in the direction of azimuth. This is due to the fact that the non-aiming eye is not in direct vertical alignment above the aiming eye when the head is held in a normal aiming position. Thus, if the non-aiming eye becomes dominant there is a tendency for the shooter to inadvertently aim to one side or the other of the target; for example, if the shooter is aiming with the right eye and the left eye becomes dominant, there will be a tendency to shoot to the left of the target, due to the different angular positions of the two eyes.
Yet another limitation of conventional shotgun sights stems from the comparatively rapid angular movement of the target. As has been described above, conventional rib-and-bead sights allow for rapid acquisition of a fast-moving target. However, the rapid movement of the target also means that the shooter must xe2x80x9cleadxe2x80x9d the target by aiming along its projected path, and conventional sights provide little or nothing in the way of a visual reference by which the shooter can accurately judge the line of flight and thereby determine a proper lead angle.
Accordingly, there exists a need for a method and apparatus for assisting a shooter in maintaining his aiming eye at the proper elevation relative to the rib and front bead when using a shotgun. Furthermore, there exists a need for such a method and apparatus that does not interfere with the ability of the shooter to rapidly acquire the target and point the shotgun when using rib-and-bead sights. Still further, there exists a need for such a method and apparatus that provides the shooter with a distinctive and virtually instantaneous indication when his eye has been raised above the proper level, so that the shooter is able to reposition his head in a quick and reflexive manner. Still further, there exists a need for such a method and apparatus that encourages proper side-to-side alignment of the sighting eye and also inhibits cross-dominance by the non-sighting eye. Still further, there exists a need for a method and apparatus that assists the shooter in determining the flight angle of targets so as to determine the proper angle of the lead. Still further, there exists a need for such a method and apparatus that is lightweight and simple in construction, and which does not encumber the shotgun or impair its handling. Still further, there exists a need for such a method and apparatus that is sufficiently reliable to be used in a field environment, and that is sufficiently inexpensive to manufacture that it can be made widely available to shooters and hunters.
The present invention has solved the problems cited above, and is a method for assisting a shooter with holding an aiming eye at a predetermined proper orientation relative to the barrel of the shotgun.
The method may comprise the steps of forming a visual display, and presenting the display to the aiming eye along a path that extends at a predetermined rearward angle over the barrel such that at a predetermined longitudinal position of the aiming eye the path is at the proper level for the aiming eye to be held relative to the barrel, so that in response to being lifted above the path, the aiming eye sees a change in image that provides the shooter with a visual indication that the aiming eye has been raised above the proper level relative to the barrel.
In a preferred embodiment, the step of presenting the display may comprise projecting light from a forward portion of the barrel towards the predetermined position of the aiming eye. The step of projecting light from a forward portion of the barrel may comprise reflecting light from a refractive surface so as to disperse the light into at least two different colors, so that a first color is received by the aiming eye when aligned with the path and a second color is received by the aiming eye when raised above the path. The step of reflecting light from a refractive surface may comprise reflecting light from a diffraction grating on the barrel so that at least a partial spectrum is projected along the path towards the aiming eye.
The step of projecting light from a forward portion of the barrel may also comprise projecting light from a lenticular sheet on the barrel, so that a first projected image is received by the aiming eye when aligned with the path and a second projected image is received by the aiming eye when raised above the path.
The step of projecting light from a forward portion of the barrel may also comprise projecting light from overlapping repetitive patterns on the barrel so as to generate a moirxc3xa8 effect, so that a first moirxc3xa8 pattern is received by the aiming eye when aligned with the path and a second moirxc3xa8 pattern is received by the aiming eye when raised above the path.
The step of projecting light from the forward portion of the barrel may also comprise reflecting light from at least one mirror surface, so that the reflected light is received by the aiming eye when on a first side of the path and is not received by the aiming eye on an opposite side of the path. This step may also comprise providing at least one substantially planar surface having a contrasting color or reflective surface thereon, with the planar surface extending at an angle substantially in alignment with the path to the aiming eye, so that the contrasting color or reflection is not visible to the aiming eye when aligned with the path and becomes visible to the aiming eye when the eye is raised above the path.
The step of forming the display may comprise reflecting light from an ambient source or may comprise projecting a beam of light from an artificial source. The artificial light source may be an LED, or may be a lighted sight tube.
The step of presenting a visual display may comprise dispersing a beam of light into at least two different colors so that a first color received by the aiming eye when aligned with the path and a second color is received by the aiming eye when above the path. The step of dispersing the beam of light into different colors may comprise reflecting a beam of light from a diffraction grating so as to disperse the beam into at least a partial spectrum that is projected along a path towards the aiming eye. The step of reflecting a beam of light on a diffraction grating may comprise projecting a beam of light forwardly against the front sight of the shotgun, and reflecting the forwardly projected beam of light from a concave diffraction grating on the rearward side of the sight.
The step of dispersing the beam of light may also comprise passing a beam of light through a prism so as to disperse the beam into at least a partial spectrum that is projected along the path towards the aiming eye. The step of passing a beam of light through the prism may comprise projecting a beam of light rearwardly from proximate the front sight of the shotgun, and passing the rearwardly projected beam through a prism mounted along the barrel of the shotgun so as to be positioned between a front sight and the aiming eye.
The step of forming a display may also comprise gathering ambient light with at least one fiber-optic rod on the forward portion of the barrel. The step of presenting the visual display may comprise positioning an end surface of at least one fiber optic rod or pair of fiber-optic rods at an angle substantially in alignment with the path to the aiming eye, so that light projected at the end surface of the fiber-optic rod is not visible to, the aiming eye when the eye is aligned with the path, and the light becomes visible when the eye is raised above the path.
The step of presenting the visual display to the aiming eye may further comprise presenting the display so that a first image is seen by the aiming eye when in proper alignment with the barrel in azimuth, and a change in the image is seen by an eye when not in proper alignment with the barrel, so that the change in image provides the shooter with a visual indication that the aiming eye has been moved from proper alignment with the barrel in azimuth or of cross dominance by the non-aiming eye.
The step of presenting the visual display to the aiming eye may further comprise presenting the display so that an indication of elevational and azimuth alignment may be ascertained simultaneously. In a preferred embodiment, the step of presenting the display for conjunctive elevational and azimuth alignment may comprise two substantially planar lenticular or diffractive surfaces on the forward portion of the barrel, such that the optical features of their lenses are orthogonally oriented to provide an indication of alignment in mutually orthogonal directions, one lenticular surface displaying a visual change when the elevation of the sighting eye transitions between a predefined vertical angle which defines the zone of accurate elevational eye alignment, and the other displaying a visual change when the azimuth of the sighting eye transitions between a predefined horizontal angle which defines the zone of accurate azimuth eye alignment.
The present invention further provides an apparatus for assisting a shooter in holding an aiming eye at a predetermined proper level relative to the barrel of a shotgun.
The apparatus may comprise means for forming a visual display, and a means for presenting the display to the aiming eye along a path that extends at a predetermined rearward angle over the barrel such that a predetermined longitudinal position of the aiming eye the path is at a proper level for the aiming eye to be held lightly to the barrel, so that in response to being lifted above the path the aiming eye sees a change in image that provides the shooter with a visual indication that the aiming eye has been raised above the proper level relative to the barrel.
In a preferred embodiment, there is an apparatus for assisting a shooter in holding an aiming eye at a proper level relative to a barrel of a shotgun, comprising a light source for mounting at a front sight of the shotgun so as to project a beam of light rearwardly therefrom, and a refractive surface that is mountable to a raised rib on the barrel of a shotgun so as to reflect and diffuse the beam of light into at least first and second different colors divided along a generally horizontal plane extending at a predetermined rearward and upward angle, so that the first color is received by the aiming eye when the aiming eye is below the plane, so as to indicate to the shooter that the aiming is at the proper level relative to the barrel, and the second color is received by the aiming eye when the eye is above the plane, so as to indicate to the shooter that the aiming eye has been raised above the proper level relative to the barrel.
The refractive surface may comprise a diffraction grating, and may be mounted on an inverted U-shaped channel for detachably fitting over and engaging the raised rib on the barrel.